Yes, the former Libyan intelligence agent is purportedly dying of cancer. But as a London Times columnist asked: Would the same Scots release Robert Black, the Scottish serial killer of young girls, if he were on death's door?

Clearly something is going on here that has little to do with compassion. Americans, who remember the Lockerbie tragedy with horror, deserve to know the real reason Megrahi was freed.

The most likely possibility falls under the heading "business and blackmail." The Brits have extensive trade interests in Libya, and Megrahi had become an obstacle to them. (No one believes British Prime Minister Gordon Brown's claim that the decision rested solely with Scottish officials.)

As Saif Gadhafi, a son of Libya's leader, put it last week, "In all commercial contracts for oil and gas with Britain, Megrahi was always on the negotiating table."

His father, the mercurial Moammar, went out of his way to embarrass Brown, along with Queen Elizabeth and her son Prince Andrew (a regular visitor to Libya on trade missions), by thanking them publicly for their alleged role in Megrahi's release.

The British had been seeking to unload Megrahi for some time since Gadhafi's renunciation of terrorism and his scrapping of Libya's weapons of mass destruction in 2003.

Tehran had authorized and funded the bombing, he said, as a reprisal for the accidental U.S. shoot-down of an Iranian civilian airliner over the Persian Gulf in July 1988.

But this operation was foiled in October 1988 by German intelligence, which broke up a PFLP-GC cell in Frankfurt. The Lockerbie bombing was two months later.

Cannistraro believes the PFLP-GC handed off the operation to the Libyans.

The explosive device that destroyed Pan Am 103 was placed in a Toshiba cassette player -- just like the bombs found in the Frankfurt bust. "There is no question in my mind that the Libyans carried this operation off," he said.

Among the other questions that surround the Megrahi affair is what role, if any, the Obama administration had in it.

Once Megrahi was released, it was dumb for the Brits or the Americans to expect Gadhafi to refrain from giving him a big public reception.

Indeed, the Libyan leader is planning to honor the convicted bomber at next month's 40th-anniversary celebration of the coup that brought him to power.